Image-guided procedures are becoming increasingly popular in the field of medicine. Image-guided procedures, such as image-guided surgeries, generally make use of tracked surgical instruments and tracked locations on a patient's body in conjunction with corresponding three-dimensional volume images, thereby making the surgical process more accurate and less invasive.
Before an image-guided procedure commences, registration between the anatomical region to be operated upon and its pre-acquired image is performed. This registration is a process of estimating an optimal transformation, or coordinate mapping, between two different reference coordinate systems or frames: one in which image locations are specified and the other in which locations in the anatomical regions are specified.